SILVER SPRING, Md., Sept. 19 ‚ÄĒ Federal scientists urged stronger warning labels Thursday on every bottle of acetaminophen, based on evidence that thousands of Americans may unwittingly take toxic doses that could harm their livers.

‚ÄúYou cannot allow more innocent men, women and children to suffer,‚ÄĚ Kate Trunk, whose 23-year-old son Marcus was one of about 100 people thought to die every year from unintentional overdoses, told a panel of Food and Drug Administration advisers. ‚ÄúDeath is not an acceptable side effect.‚ÄĚ

The FDA panel voted 21-1 to back her call for more warnings about the risk.

Some 100 million people a year take acetaminophen, and serious liver damage is very rare, manufacturers insist. Although best known by the Tylenol brand, acetaminophen is in almost 200 different branded and generic products, from headache relievers to cold-and-cough remedies. While mostly sold without a...